Diabetes mellitus, often referred to as diabetes, is a chronic condition in which a person has elevated blood glucose levels that result from the body's inability to produce insulin, use insulin, or both. There are three main types of diabetes. Type 1 diabetes usually strikes children and young adults and is linked to conditions such as autoimmune, genetic, environmental, or a combination. Type 2 diabetes accounts for 90-95% of diabetes cases and is linked to obesity and physical inactivity. Gestational diabetes is a form of glucose intolerance diagnosed during pregnancy and usually resolves soon after delivery.
In 2013, some 382 million people worldwide are estimated to have diabetes, and an estimated 5.1 million people between the ages of 20 and 79 die from diabetes annually, according to the International Diabetes Foundation Diabetes Atlas. In the United States, nearly 24 million Americans have diabetes with an estimated 25 percent of seniors age 60 and older being affected, according to The Centers for Disease Control and Prevention. Diabetes costs are estimated to be $174 billion in the United States alone every year, according to the National Diabetes Information Clearinghouse. Without treatment, diabetes can lead to severe complications such as heart disease, stroke, blindness, kidney failure, amputations, and death related to pneumonia and flu.
Handheld blood glucose meters are used by persons with diabetes to measure blood glucose using a test strip inserted into the meter. The test strip has a collection area on the end of the strip extending from the meter. A small drop of blood is placed on the collection area to initiate an enzymatic reaction to determine a blood glucose measurement. This enzymatic reaction is sensitive to temperature, so an acceptable temperature range is established for preforming accurate blood glucose measurements. Prior to beginning a blood glucose measurement, a temperature sensor typically inside the meter housing measures temperature to determine whether the temperature is within the acceptable temperature range. If the temperature is within the acceptable temperature range, a glucose measurement is performed. If the temperature is outside the acceptable temperature range, a glucose measurement is not performed.
As handheld blood glucose meters have increased in capability with features such as color displays, multiple microprocessors, and wireless communications power consumption has increased leading to the use of rechargeable batteries. During recharging, the charging current and electrochemical reactions cause the battery to self-heat or warm which causes a temperature rise inside the housing or self-heating, particularly during the first hour or two of recharging. When the blood glucose meter rises in temperature, the meter's estimate for the acceptable temperature range to perform a blood glucose test can be inaccurate. Modulating charging current during a recharging session can create self-heating thermal conditions that are difficult to predict. An inaccurate temperature measurement can cause a lock-out condition that prevents a blood glucose measurement from being performed or mask a lock-out condition that inappropriately allows a blood glucose measurement to be performed, potentially for the first hour of recharging. Examples of rechargeable handheld analyte meters include LifeScan, OneTouch Verio IQ Blood Glucose Monitoring System; Bayer, Contour® USB Glucose Monitoring System; and Roche Diagnostics, Accu-Chek® Inform II Blood Glucose Monitoring System.
What is needed is a rechargeable analyte meter with recharging control to manage battery self-heating for improved analyte testing.